Converging anatomical and physiological evidence reveal that the nucleus accumbens (NAcc) is involved in regulating behavior directed toward food and drug reinforcement. Interestingly, exposure to environmental complexity reduces behavioral responding for rewards (including drugs of abuse) and alters NAcc function. I hypothesize that exposure to environmental enrichment attenuates the reinforcing effects of incentive stimuli by altering neural circuitry involved in the regulation of goal-directed behavior; however, it is unknown what influence differential environmental exposure has on the electrophysiology of the NAcc during goal-directed behavior. Since subregions of NAcc (core and shell) may be involved in different aspects of motivated behavior, I propose to assess neuronal activity from both of these brain areas in standard-housed (SH), enviromentally-enriched (EE), and socially-isolated (SI) rats in a conditioned reinforcement task. Because behavioral differences exist in EE and SI animals during task acquisition (see Experiment 2, Preliminary Data), we will also record from core and shell of these animals during task learning. This data will not only add to our understanding of the role of NAcc core and shell in goal-directed activity but may also provide insight to neural mechanisms underlying drug-seeking behavior and thus may have important implications for the treatment of drug addiction.